This proposal is for a NIAAA Mentored Clinical Scientist Development Award (KO8) to foster the development of Dr. Elliot Nelson's career by supporting his work with Dr. Andrew Heath and Dr. Richard Todd. The award will enable the candidate to explore the relationship of alcohol dependence and social phobia, controlling for comorbid major depressive disorder (MDD). The candidate's career development will include a program of formal coursework and independent tutorials focusing on biostatistics, genetic epidemiology, research methodology (including the mediation of alcohol dependence and dangerous behavior risks), and behavioral and quantitative genetics. The skills acquired will be applied to both the analysis of existing data and to an independent research project designed to provide a better understanding of the mediation of shared risk. The preliminary data from adolescent female twins suggests that comorbid alcohol dependence is likely to be seen at increased rates in individuals with social phobia and that these subjects are also at increased risk for dangerous behaviors such as having unprotected sex, suicidal ideation, suicide plans, and suicide attempts. The goals of the proposal are to collect two waves of data on l00 control pairs and l00 pairs where at least one twin has a history of social phobia. We will use these data, plus existing data-sets, to address the following Specific Aims: l) To characterize prospectively the profile of comorbid illness observed in individuals with social phobia; 2) To determine prospectively the risk for alcohol dependence and harmful alcohol use given a primary diagnosis of social phobia; 3) To use multivariate twin analysis to characterize the relative contributions of disorder-specific and shared genetic and environmental risk factors for social phobia, alcohol dependence, and MDD; 4) To examine whether a variety of dangerous behaviors are seen more frequently in individuals with social phobia, and determine their association with the development of alcohol problems; 5) To examine the routes by which the shared risks appear to be mediated (including both risks of comorbid illness and dangerous behaviors).